U.S. patent number 6,090,572 [Application Number 09/105,309] was granted by the patent office on 2000-07-18 for filtration and extraction device and method of using the same.
This patent grant is currently assigned to Biostar, Incorporated. Invention is credited to Mark A. Crosby.
United States Patent |
6,090,572 |
Crosby |
July 18, 2000 |
Filtration and extraction device and method of using the same
Abstract
The present invention involves a simple, disposable, manual
filtration and extraction device and method of use that provides a
sample directly to an analytical method. The device is capable of
providing a clarified liquid ready for analysis or disposal as
appropriate for the specific analyte of interest, and is capable of
capturing particulate materials and allowing for further extraction
of those particles directly with the device. Once extracted, the
device will deliver a liquid containing the analyte of interest to
an analytical method. The filtration and extraction devise includes
a pliant body having an open top end and an internal wall defining
an inner chamber. A sealing mechanism is adapted to seal the open
top end of the body. A gradient filter assembly including at least
one filter is supported by a support assembly carried by the body.
The pliant body is adapted to be squeezed by a user's fingers so as
to impart a positive pressure in the chamber sufficient to cause a
fluid in the chamber to flow through the filter assembly.
Inventors: |
Crosby; Mark A. (Boulder,
CO) |
Assignee: |
Biostar, Incorporated (Boulder,
CO)
|
Family
ID: |
22305113 |
Appl.
No.: |
09/105,309 |
Filed: |
June 26, 1998 |
Current U.S.
Class: |
435/29; 422/68.1;
435/257.6; 435/23; 435/30; 435/34; 435/295.3; 435/4; 435/293.1;
435/283.1 |
Current CPC
Class: |
B01D
29/78 (20130101); C12M 33/14 (20130101); B01D
35/00 (20130101); B01D 29/822 (20130101); B01D
29/05 (20130101); B01D 2201/202 (20130101); Y10S
435/975 (20130101) |
Current International
Class: |
B01D
29/01 (20060101); B01D 35/00 (20060101); C12M
1/12 (20060101); B01D 29/05 (20060101); C12Q
001/02 (); C12Q 001/00 (); C12Q 001/37 (); C12Q
001/04 () |
Field of
Search: |
;435/29,4,23,28,30,34,283.1,293.1,295.3,257.6 ;422/68.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
0 294 185 |
|
Dec 1988 |
|
EP |
|
0 471 420 |
|
Feb 1992 |
|
EP |
|
2 296 172 |
|
Jul 1976 |
|
FR |
|
Primary Examiner: Leary; Louise N.
Attorney, Agent or Firm: Brobeck, Phleger & Harrison
Claims
What is claimed is:
1. A method for filtering a biological fluid having particulate
matter and liquid and extracting one or more analytes from the
particulate matter, comprising:
providing a filtration and extraction device, comprising:
a pliant body having an open top end and an internal wall defining
an inner chamber; a sealing mechanism adapted to seal the open top
end of the body; a gradient filter assembly including at least one
filter; a support assembly carried by the body, the gradient filter
assembly supported by the support assembly;
adding the biological fluid to the chamber through the open top
end;
sealing and closing the open top end with the sealing
mechanism;
causing biological fluid to flow through the filter assembly so
that the particulate matter is retained by the filter assembly and
the liquid is expressed from the device by squeezing the pliant
body so that a positive pressure is imparted to the chamber;
unsealing and opening the open top end of the body;
adding at least one reagent to the chamber though the open top end;
and
causing at least one reagent to flow through said filter assembly
so that the one or more analytes from the particulate matter are
extracted by the at least one reagent and expressed therewith from
the device for a further diagnostic assay method by squeezing the
pliant body so that a positive pressure is imparted to the
chamber.
2. The method of claim 1, wherein the body is tubular.
3. The method of claim 2, wherein the body is made of PVC.
4. The method of claim 1, wherein the body includes a rigid ring at
the top end.
5. The method of claim 1, wherein the body includes an open bottom
end and the support assembly is carried by the body near the open
bottom end.
6. The method of claim 1, wherein the sealing mechanism is a
sealing cap.
7. The method of claim 6, wherein the sealing cap is made of PVC
and is attached to the body.
8. The method of claim 1, wherein the support assembly includes a
nozzle adapted to express fluid from said device.
9. The method of claim 1, wherein the support assembly includes a
circular, concave support that supports said filter assembly.
10. The method of claim 9, wherein the support includes a plurality
of radial support ribs that support said filter assembly.
11. The method of claim 1, wherein the support assembly includes a
flat bottom surface for standing the device in an upright position
on a flat surface.
12. The method of claim 1, wherein the support assembly is made of
a rigid material.
13. The method of claim 1, wherein the filter assembly includes a
pore size that ranges from 0.5 to 4 microns.
14. The method of claim 1, wherein the at least one filter is made
of a material selected from the group consisting of polysulfone,
nylon, polypropylene, cellulose, and cellulose acetate.
15. The method of claim 1, wherein the filter is hydrophilic.
16. The method of claim 1, wherein filter assembly includes a
single gradient filter.
17. The method of claim 16, wherein the effective pore size of the
filter is in the range of 0.69 to 0.87 microns.
18. The method of claim 1, wherein the filter assembly includes
multiple homogeneous filters with at least two of the filters
having a different pore size, and the multiple filters stacked so
that a filter with a smaller pore size is located below a filter
with a larger pore size.
19. The method of claim 18, wherein a woven nylon membrane is
located between filters.
20. The method of claim 1, wherein the filter assembly includes a
periphery that is flush with the internal wall of the body.
21. The method of claim 1, wherein the biological fluid is
urine.
22. The method of claim 1, wherein the one or more analytes is a
lipopolysacharride obtained from Chlamydia.
23. The method of claim 1, wherein the one or more analytes is a
protein from the outer cell wall of Neisseria gonorrhea.
24. The method of claim 1, wherein the particulate matter includes
a virus that the one or more analytes is extracted from.
25. The method of claim 1, wherein the particulate matter includes
bacteria that the one or more analytes is extracted from.
26. The method of claim 1, further including dispensing the at
least one reagent into multiple test containers to test for
different analytes.
27. The method of claim 1, further including using the expressed
liquid in a diagnostic method for determining the presence of an
analyte.
28. The method of claim 1, further including detecting the presence
of an analyte expressed from the device using a diagnostic
procedure selected from the group consisting of radio-immunoassay,
optical immunoassay, enzyme immunoassay, nucleic acid
amplification, chemilluminescence, and surface plasmon
resonance.
29. A method for filtering a biological fluid, comprising:
providing a filtration device, comprising:
a pliant body having an open top end and an internal wall defining
an inner chamber; a sealing mechanism adapted to seal the open top
end of the body; a gradient filter assembly including at least one
filter; a support assembly carried by the body, the gradient filter
assembly supported by
the support assembly;
adding the biological fluid to the chamber through the open top
end;
sealing and closing the open top end with the sealing mechanism;
and
causing biological fluid to flow through the filter assembly so
that the particulate matter is retained by the filter assembly and
a clarified liquid is expressed from the device by squeezing the
pliant body so that a positive pressure is imparted to the
chamber.
30. The method of claim 29, further including using the expressed
liquid in a diagnostic method for determining the presence of an
analyte.
31. A method for filtering urine and extracting one or more
lipopolysacharride analytes from one or more Chlamydia
microorganisms, comprising:
providing a filtration and extraction device, comprising:
a pliant body having an open top end and an internal wall defining
an inner chamber; a sealing mechanism adapted to seal the open top
end of the body; a gradient filter assembly including at least one
filter; a support assembly carried by the body, the gradient filter
assembly supported by the support assembly;
adding a urine sample to the chamber through the open top end;
sealing the open top end with the sealing mechanism;
squeezing the pliant body so that a positive pressure is imparted
to the chamber sufficient to cause the urine to flow through said
filter assembly so that the one or more Chlamydia microorganisms
are retained by the filter assembly and a clarified liquid is
expressed from the device;
unsealing the open top end of the body;
adding a protease extraction reagent to the chamber though the open
top end;
adding an alkaline detergent extraction reagent to the chamber
though the open top end; and
squeezing the pliant body so that a positive pressure is imparted
to the chamber sufficient to cause the reagents to flow through
said filter assembly so that the one or more lipopolysacharride
analytes from the one or more retained Chlamydia microorganisms are
extracted by at least one of the reagents and expressed therewith
from the device for a further diagnostic assay method.
32. The method of claim 31, further including detecting the
presence of the one or more lipopolysacharride analytes using an
optical immunoassay diagnostic procedure.
33. A method for filtering urine and extracting one or more
analytes from one or more Chlamydia microorganisms and/or one or
more analytes from one or more Neisseria gonorrhoeae
microorganisms, comprising:
providing a filtration and extraction device, comprising:
a pliant body having an open top end and an internal wall defining
an inner chamber; a sealing mechanism adapted to seal the open top
end of the body; a gradient filter assembly including at least one
filter; a support assembly carried by the body, the gradient filter
assembly supported by the support assembly;
adding a urine sample to the chamber through the open top end;
sealing the open top end with the sealing mechanism;
squeezing the pliant body so that a positive pressure is imparted
to the chamber sufficient to cause the urine to flow through said
filter assembly so that the one or more Chlamydia microorganisms
and/or the one or more Neisseria gonorrhoeae microorganisms are
retained by the filter assembly and a clarified liquid is expressed
from the device;
unsealing the open top end of the body;
adding an alkaline detergent extraction reagent to the chamber
though the open top end; and
squeezing the pliant body so that a positive pressure is imparted
to the chamber sufficient to cause the reagent to flow through said
filter assembly so that the one or more analytes from the one or
more Chlamydia microorganisms and/or the one or more analytes from
the one or more Neisseria gonorrhoeae microorganisms are extracted
by the extraction reagent and expressed therewith from the device
into two or more extraction containers for further extraction.
34. The method of claim 33, wherein the extraction reagents and
analytes are expressed into a first extraction container and a
second extraction container, the method further including adding a
protease extraction reagent to the first extraction container for
extracting one or more analytes and a neutralization reagent to the
first extraction container, and adding a neutralization reagent to
the second extraction container.
35. The method of claim 34, further including detecting the
presence of the one or more analytes in the respective extraction
containers using respective optical immunoassay diagnostic
procedures.
Description
FIELD OF THE INVENTION
The present invention relates to devices and methods for filtration
of a biological fluid and/or extraction of a specific analyte from
a suspended particulate.
BACKGROUND OF THE INVENTION
It is often desirable to analyze a specific component, compound, or
analyte within a biological fluid such as urine. Frequently, this
involves analyzing a liquid or a particulate of the biological
fluid. Centrifugation is commonly used to separate a liquid
solution from a particulate suspended within the liquid solution.
Once separated by centrifugation the fluid is readily available for
analysis. If, however, an analyte of interest is in the deposited
particulate material, a more complicated process is required. The
particulate material must be re-suspended and transferred from a
centrifuge tube to an analysis tube. If the particulate material
must be extracted prior to analysis, one or more reagents may be
introduced directly into the centrifuge tube or may be introduced
to the transferred, re-suspended sample in the analysis tube. If,
after extraction, the analyte must be separated from other larger
particulates, the sample may halve to be re-centrifuged or filtered
prior to analysis.
There are a number of drawbacks to the use of centrifugation.
Centrifugation equipment is costly and requires a substantial
amount of space. Certrifugation is a labor burden and a time burden
for the operator because the centrifuge has to be loaded and
unloaded. Operator error also can occur with centrifugation.
Smaller, less expensive centrifugation equipment is available, but
this does not eliminate the time required to process a sample, and
may increase the processing time to provide adequate
separation.
Plunger-like in-container pressure filtration systems have been
designed to separate particles from liquid samples being tested in
an effort to eliminate the necessity of centrifugation. A number of
these systems involve a tube such as a test tube and a plunger
mechanism that reciprocates axially within the tube. The plunger
mechanism includes a filter unit at a distal end of the plunger
mechanism. Downward axial movement of the filter unit via the
plunger mechanism compacts particulates in the liquid sample at the
bottom of the tube. Any material greater than the pore size of the
filter is trapped under the filter assembly. The liquid solution
can be decanted or aspirated away.
A problem with these plunger-like devices and similar devices is
that they do not allow for easy recovery of the particulate
material for subsequent processing. Also, the filter unit is
subject to sufficient pressure during the plunging process, which
can cause the filter to crack or tear. Often such devices are used
with a tapered tube. Upon downward axial movement of the plunger
mechanism, the diameter of the plunger mechanism and the filter
unit may become the same as the inner diameter of the tapered tube.
This may prevent the filter unit from being forced through the
solution. If all of the liquid has not been filtered though the
device, then residual liquid may contaminate the particulate
material. The volume of liquid may not be easily detectable or
apparent, but the contamination can be substantial. Forcing the
plunger mechanism further into the tube can cause the tube to crack
or break. If the plunger mechanism is not designed for removal,
additional processing such as extraction of the solid within the
same device may be impossible. A more complete multiple unit or
multiple module device may be required that includes a removable
module designed to capture the solid.
SUMMARY OF THE INVENTION
To this end, a first aspect of the present invention involves an
easy to use biological fluid filtration and extraction device that
provides a sample directly to an analytical method. The device is
capable of providing a clarified liquid ready for analysis or
disposal as appropriate for the specific analyte of interest, and
is capable of capturing particulate materials and allowing for
further processing, i.e., extraction, of those particles directly
with the device. Once extracted, the device will deliver a liquid
containing the analyte of interest to an analytical method. The
device includes a pliant body having an open top end and an
internal wall defining an inner chamber. A sealing mechanism is
adapted to seal the open top end of the body. A gradient filter
assembly including at least one filter is supported within the body
by a support assembly. The pliant body is adapted to be squeezed by
a user's fingers so as to impart a positive pressure in the chamber
sufficient to cause a fluid in the chamber to flow through the
filter assembly.
In a preferred embodiment of the filtration and extraction device,
the device includes a number of features. A first feature is that
the body is tubular and made of polyvinylchloride. A second feature
is that the body includes a rigid ring at the top end. A third
feature is that the body includes an open bottom end and the
support assembly is carried by the body near the open bottom end. A
fourth feature is that the sealing mechanism is a polyvinylchloride
sealing cap. A fifth feature is that the support assembly includes
a nozzle adapted to dispense the fluid from the device. A sixth
feature is that the support assembly includes a circular, concave
support that supports the filter assembly, and the support includes
a plurality of radial support ribs that support the filter
assembly. A seventh feature is that the support assembly includes a
flat bottom surface for standing the device in an upright position
on a flat surface. An eighth feature is that the support assembly
is made of a rigid material. An ninth feature is that the filter
assembly includes a pore size that ranges from 0.5 to 4 microns. A
tenth feature is that the at least one filter is made of
polysulfone, nylon, polypropylene, cellulose, or cellulose acetate.
An eleventh feature is that the filter is hydrophilic. A twelfth
feature is that filter assembly includes a single gradient filter
and the effective pore size of the filter is in the range of 0.69
to 0.87 microns. A thirteenth feature is that the filter assembly
includes multiple homogeneous filters with at least two of the
filters having a different pore size, the multiple filters stacked
so that a filter with a smaller pore size is located below a filter
with a larger pore size, and a woven nylon membrane is located
between filters. A fourteenth feature is that the periphery of the
filter assembly is flush with the internal wall of the body.
A second aspect of the invention involves a filtration device
including a pliant tubular body having an open end and an internal
chamber, means for sealing the open end, a gradient filter assembly
including at least one filter, and means for supporting the filter
assembly within the tubular body, whereby the pliant tubular body
is adapted to be squeezed by a user's fingers so as to impart a
positive pressure in the chamber sufficient to cause a fluid in the
chamber to flow through the filter assembly.
A third aspect of the invention includes a kit for filtering a
biological fluid having particulate matter and liquid, and
extracting an analyte from the particulate matter. The kit includes
a filtration and an extraction device including a pliant tubular
body having an open top end, an open bottom end, and an internal
wall defining an inner chamber. The device further includes a cap
assembly fixed to the body near the open top end. The cap assembly
includes a cap adapted to seal the open top end. The device also
includes a support assembly fixed to the body near the open bottom
end, the support assembly including a circular support located
within the tubular body and a nozzle adapted to dispense fluid from
the device. A circular gradient filter assembly including at least
one filter is fixed to the support. The pliant body is adapted to
be squeezed by a user's fingers so as to impart a positive pressure
in the chamber sufficient to cause a fluid in the chamber to flow
through the filter assembly. The kit also includes at least one
reagent for extracting the analytes from the particulate matter and
a neutralization reagent for neutralizing the at least one
reagent.
In a preferred embodiment of the aspect of the invention described
immediately above, the at least one reagent is a protease
extraction reagent and/or an alkaline detergent extraction
reagent.
A fourth aspect of the invention involves a method for filtering a
biological fluid having particulate matter and liquid and
extracting one or more analytes from the particulate matter a
device such as that described in the first aspect of the invention.
The method includes adding the biological fluid to the chamber
through the open top end, sealing the open top end with the sealing
mechanism, squeezing the pliant body so that a positive pressure is
imparted to the chamber sufficient to cause the biological fluid to
flow through the filter assembly so that the particulate matter is
retained by the filter assembly and the liquid is expressed from
the device, unsealing the open top end of the body, adding at least
one reagent to the chamber though the open top end, and squeezing
the pliant body so that a positive pressure is imparted to the
chamber sufficient to cause the at least one reagent to flow
through the filter assembly so that the one or more analytes from
the particulate matter are extracted by the at least one reagent
and expressed therewith from the device for a further diagnostic
assay method.
A preferred embodiment of the aspect of the invention described
immediately above includes a number of features. Features one
through fourteen were already identified in the first aspect of the
invention described above. A fifteenth feature is that the
biological fluid is urine. A sixteenth feature is that the one or
more analytes is a lipopolysacharride obtained from Chlamydia and a
protein from the outer cell wall of Neisseria gonorrhea. A
seventeenth feature is that the particulate matter includes a virus
or a bacteria that the one or more analytes is extracted from. An
eighteenth feature is dispensing the at least one reagent into
multiple test containers to test for different analytes. A
nineteenth feature is using the expressed liquid in a diagnostic
method for determining the presence of an analyte. A twentieth
feature includes detecting the presence of an analyte expressed
from the device using a diagnostic procedure such as
radio-immunoassay, optical immunoassay, enzyme immunoassay, nucleic
acid amplification, chemilluminescence, and surface plasmon
resonance.
A fifth aspect of the invention involves a method for filtering a
biological fluid using a device such as that described in the first
aspect of the invention. The method includes adding the biological
fluid to the chamber through the open top end, sealing the open top
end with the sealing mechanism, and squeezing the pliant body so
that a positive pressure is imparted to the chamber sufficient to
cause the biological fluid to flow through the filter assembly so
that particulate matter is retained by the filter assembly and a
clarified liquid is expressed from the device.
A preferred embodiment of the aspect of the invention immediately
described above includes a number of features. A first feature
involves using the expressed liquid in a diagnostic method for
determining the presence of an analyte.
A sixth aspect of the invention involves a method for filtering
urine and extracting one or more lipopolysacharride analytes from
one or more Chlamydia microorganisms using a device such as that
described in the first aspect of the invention. The method includes
adding a urine sample to the chamber through the open top end,
sealing the open top end with the sealing mechanism, squeezing the
pliant body so that a positive pressure is imparted to the chamber
sufficient to cause the urine to flow through the filter assembly
so that the one or more Chlamydia microorganisms are retained by
the filter assembly and a clarified liquid is expressed from the
device, unsealing the open top end of the body, adding a protease
extraction reagent to the chamber though the open top end, adding
an alkaline detergent extraction reagent to the chamber though the
open top end, and squeezing the pliant body so that a positive
pressure is imparted to the chamber sufficient to cause the
reagents to flow through the filter assembly so that the one or
more lipopolysacharride analytes from the one or more retained
Chlamydia microorganisms are extracted by at least one of the
reagents and expressed therewith from the device for a further
diagnostic assay method.
In a preferred embodiment of the aspect of the invention described
immediately above, the method includes detecting the presence of
the one or more lipopolysacharride analytes using an optical
immunoassay diagnostic procedure.
A seventh aspect of the invention involves a method for filtering
urine and extracting one or more analytes from one or more
Chlamydia microorganisms and/or one or more analytes from one or
more Neisseria gonorrhoeae microorganisms using a device such as
that described in the first aspect of the invention. The method
includes adding a urine sample to the chamber through the open top
end, sealing the open top end with the sealing mechanism, squeezing
the pliant body so that a positive pressure is imparted to the
chamber sufficient to cause the urine to flow through the filter
assembly so that the one or more Chlamydia microorganisms and/or
the one or more Neisseria gonorrhoeae microorganisms are retained
by the filter assembly and a clarified liquid is expressed from the
device, unsealing the open top end of the body, adding an alkaline
detergent extraction reagent to the chamber though the open top
end, and squeezing the pliant body so that a positive pressure is
imparted to the chamber sufficient to cause the reagent to flow
through the filter assembly so that the one or more analytes from
the one or more Chlamydia microorganisms and/or the one or more
analytes from the one or more Neisseria gonorrhoeae microorganisms
are extracted by the extraction reagent and expressed therewith
from the device into two or more extraction containers for
attempting further extraction.
In a preferred embodiment of the aspect of the invention described
immediately above, the method includes a number of features. A
first feature is that the extraction reagents and analytes are
expressed into a first extraction container and a second extraction
container, and the method further includes adding a protease
extraction reagent to the first extraction container for extracting
one or more analytes and a neutralization reagent to the first
extraction container, and adding a neutralization reagent to the
second extraction container. A second feature includes detecting
the presence of the one or more analytes in the respective
extraction containers using respective optical immunoassay
diagnostic procedures.
Other features and advantages of the inventions are set forth in
the following detailed description and drawings, which are intended
to illustrate, but not limit, the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a filter and extraction
device in accordance with a preferred embodiment of the
invention;
FIG. 2 is a perspective view of the filter and extraction device
illustrated in FIG. 1 in an assembled state; and
FIG. 3 is a cross-sectional view of the filter and extraction
device illustrated in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to FIGS. 1-3, a filtration and extraction device 10
constructed in accordance with a preferred embodiment of the
invention will now be described. The filtration and extraction
device 10 includes a pliable tubular body 12, a cap assembly 14, a
support assembly 16, and a filter assembly 18. The filtration and
extraction device 10 is a simple, one-piece, manual apparatus that
provides a sample directly to an analytical assay method and
eliminates the aforementioned centrifugation step.
In use, a user adds a biological fluid to the tubular body 12,
seals the
tubular body 12 with the cap assembly 14, and squeezes the tubular
body 12 with one's fingers, causing the fluid to pass through the
filter assembly 18. Particulate matter in the biological fluid is
retained by the filter assembly 18 for further processing, if
desired, and clarified liquid is expressed from the device 10 for
further processing and/or analysis if desired. If extraction of an
analyte of interest from the particulate matter is desired, the
device is uncapped, one or more reagents are added to the tubular
body 12, the tubular body 12 is capped 14, pressure is applied to
the tubular body 12, causing the one or more reagents to contact
the particulate matter retained by the filter assembly 18 and the
extracted analyte to be expressed from the device 10, if
present.
The tubular body 12 includes an exterior wall 20 and an interior
wall 22. The tubular body 12 further includes a top end 26, near
where the cap assembly 14 is located, and a bottom end 28, near
where the support assembly 16 is located. A main interior chamber
24 is defined by the interior wall 22, an upper part of the filter
assembly 18, and a lower part of the cap assembly 14. The interior
chamber 24 has a volume that is sized to allow sufficient pressure
to be imported to the chamber 24 by the user's fingers so that the
biological liquid flows through the filter assembly 18 without
damaging the filter assembly 18. The tubular body 12 is made of a
soft, pliable PVC (polyvinylchloride) tubing. However, it will be
readily understood by those skilled in the art that similar
materials may be used. The PVC tubing is coextruded and cut into
lengths sufficient to allow the aforementioned pressure
characteristics in the chamber 24.
PVC is preferably used as the material for the tubular body 12
because it is inexpensive, readily available, clear, chemically
inert, biocompatible, and stable. Chemically inert means the
material is stable to deformation, discoloration, cracking,
splitting, etc. upon exposure to heat, biological fluid, extraction
reagents, diluents or other chemical solutions. Biocompatible means
the material will not bind biological materials from a solution,
affect the stability, functionality, or conformation of a
biological material upon contact with that material, or in anyway
contaminate the biological solution with components that leach from
the material in the biological solution. Stable means that the
material retains all of the above characteristics for years at room
temperature. The inertness and biocompatibility of the tubular body
12 allows a wide range of biological fluids to be processed in the
device 10.
The cap assembly 14 includes a pliable sealing cap 32 attached to
an annular support cap 34 by a hinge 36. The sealing cap 32,
annular support cap 34, and hinge 36 are injection molded of a PVC
material.
The sealing cap 32 includes an annular rim 38 surrounding a
frustoconical sunken portion 40. A tab 42 extends from the annular
rim 38.
The annular support cap 34 includes an annular rim 44 with a
central aperture 45, an outer overhang 46 having an inner wall 48,
and an inner overhang 50 having an outer wall 52 and an inner wall
53.
A rigid ring 54 circumferentially surrounds the top end 26 of the
tubular body 12 and is chemically welded thereto. The ring 54 is
injection molded of an acrylic material. The rigid acrylic ring 54
provides stiffness and support at the top end 26 of the tubular
body 12, and improves sealing of the cap 34.
The annular support cap 34 resides over the top end 26 of the
tubular body 12 and the ring 54. The inner wall 48 of the outer
overhang 46 abuts the rigid ring 54, and the outer wall 52 of the
inner overhang 50 abuts the inner wall 22 of the tubular body 12.
The acrylic ring 54 is preferably chemically welded to the exterior
wall 20 of the tubular body 12 by a cyclohexanone process, but
similar processes may be used. No carry over of the chemical agent
into the device 10 is allowed. The chemical must not alter the
components of the device 10, i.e., alter the chemical inertness or
biocompatibility, or cause cosmetic defects. A heat staking process
may also be possible to fuse the acrylic ring 54 to the exterior
20. The outer wall 52 of the inner overhang 50 is fused to the
inner wall 22 of the tubular body 12 and the inner wall 48 of the
outer overhang 46 may be chemically welded to the acrylic ring 54
in the aforementioned manner.
When capped, the undersides of the frustoconical sunken portion 40
and annular rim 38 of the pliable sealing cap 32 form a sealing
mechanism with the inner wall 53 of the inner overhang 50. This
ensures a complete seal in the cap assembly 14 at aperture 45 and
the top end 26 of the tubular body 12 so that sufficient positive
pressure can be imported to the chamber 24.
In the preferred embodiment of the invention, the support assembly
16 is a single-piece assembly made of a rigid, acrylic material.
The support assembly 16 includes an annular base 56 having a flat
bottom surface 58 and an upper surface 59, an outer overhang 60
having an inner wall 62, and an inner overhang 64 having an inner
wall 66 and an outer wall 68. The inner overhang 64 terminates at
its top into a support 72. The support 72 has a concave upper
surface 74 and a lower surface 76. The lower surface 76 of the
support 72 and the inner wall 66 of the inner overhang 64 define an
annular recess 77. The support 72 further includes a plurality of
radial support ribs 78 on the concave upper surface 74 and a
downwardly extending nozzle 80. The nozzle 80 terminates in the
annular recess 77 and includes an outlet port 82.
The single-piece support assembly 16 is made of an acrylic material
and is preferably bonded to the tubular body 12 by the
aforementioned cyclohexanone process. This bonding may occur
between the outer wall 68 of the inner overhang 64 and the inner
wall 22 of the tubular body 12. This bonding may also occur between
the bottom end 28 of the tubular body 12 and the upper surface 59
of the annular base 56, between the outer overhang 60 and the inner
overhang 64. The rigidity of the support assembly 16 gives the
bottom end 28 of the tubular body 12 stability and support. The
flat bottom surface 58 of the annular base 56 allows the device 10
to stand upright without user assistance on a flat support
surface.
In a preferred embodiment, the filter assembly 18 includes a single
circular gradient filter or membrane 84. The preferred filter 84 is
sold under the name BTS-16 Memtec membrane by the US Filter Co. of
San Diego, Calif. The membrane is a gradient membrane with an
effective pore size of 0.69 to 0.87 microns. The membrane has
sufficient tensile strength to withstand the positive pressures
required for filtration and processing without tearing. A gradient
filter means that the size of the pores decreases from the top of
the filter 84 to the bottom of the filter 84. In other words, the
pore size at the top of the filter 84 is greater than the pore size
at the bottom of the filter 84. The gradient nature of the filter
84 allows for the flow of samples across the range of types, i.e.,
clear to turbid, while ensuring the capture of the particles of
interest. A number of filter materials that are effective for this
purpose include, but not by way of limitation, polysulfones such as
Memtec, nylon, poypropylene, and cellulose, particularly cellulose
acetate. The filter 84 should be hydrophilic or treated to be
hydrophilic to reduce the non-specific capture of biologicals of
interest, i.e., analytes on the filter 84 during processing. The
hydrophilic nature of the filter 84 also ensures that the filter 84
wets well during processing. The suitable pore ranges for the
filter is 0.5 microns to 4 microns. The type of filter 84 and pore
size used depends on the particulate matter one wants to retain.
The pore size can not be so small that it would clog the filter 84,
but the pore size must be small enough to capture the particulate
matter or organism and prevent fluid flow through the filter when
no pressure is applied by the user.
Before bonding the support assembly 16 to the tubular body 12, the
filter assembly 18 is sonically welded to the support 72. When the
support assembly 18 is attached to the bottom 28 of the tubular
body 12, the periphery of the filter assembly 18 is sealed flush
with the inner wall 22 of the tubular body 12, inhibiting the
collection of liquid between the periphery of the filter assembly
18 and the inner wall 22. The underside of the filter assembly 18
is supported on the radial support ribs 78, raised slight above the
top of the outlet port 82. The concave upper surface 74 of the
support 72 provides support to the filter 84 when the filter 84
sags due to positive pressure being imparted to the chamber 24. The
support provided by the support ribs 78 and concave upper surface
74 is important for inhibiting tearing of the filter 84 under
pressure.
In an alternative embodiment, the filter assembly 18 may include a
stack of filters that mimic a single gradient filter. The filters
each have a different, homogeneous pore size and are arranged so
that a smaller pore size filter is placed below a larger pore size
filter. This type of arrangement prevents clogging in the filter
assembly 18, while allowing for the retention of the particulate
matter of interest. To prevent vapor lock between the filters, a
layer of nylon woven material sold under the name Tetko nylon
(3-20/14) by Tetko, Inc. of Depew, N.Y. is inserted between the
filters. This inhibits restricted flow that may occur as a result
of vapor lock between the filters.
In alternative embodiments, the filter assembly 18 may include a
single filter having a constant pore size, a stack of filters
having the same pore size, or a stack of filters generally
mimicking a single gradient filter, e.g., filters stacked so that
from top to bottom they generally decrease in pore size with
occasional adjacent filters having the same pore size.
The filtration and extraction device 10 will now be described
generally in use. A user first ensures that the sealing cap 32 is
removed from the top 26 of the device 10. Next, the user adds a
biological fluid to the chamber 24 through the opening 45 at the
top 26 of the device 10. The opening 45 is sufficiently wide to
allow a fluid to be easily added to the device 10.
As used herein, the term biological fluid is defined as a fluid
containing cells, viruses, yeast, and molecules of biological
origin or portions thereof, and may include urine, bladder
washings, colon washings, sputum, blood, spinal fluid, tears, nasal
secretions, vaginal secretions, or fluid from the respiratory,
alimentary, circulatory, reproductive or other body systems.
It will readily understood by those skilled in the art that the
device 10 may be applied to fluids other than biological fluids for
filtering a liquid from a solid material. The device 10 may also be
used for further processing of the solid material.
The tubular body 12 is sealed by generally aligning the sealing cap
32 over the top 26 of the tubular body 12 and pressing on the top
of the sealing cap 32 with one's thumb so that the frustoconical
sunken portion 40 of the sealing cap 32 snaps into the annular
support cap 34, near the top 26 of the tubular body 12.
It should be noted, the flat bottom surface 58 of the annular base
56 allows the device 10 to be conveniently supported in an upright
position on a flat support surface without user assistance. This is
desirable when adding a fluid to the device 10 or in between
procedural steps.
Next, the biological fluid is filtered and expressed from the
device 10. This is accomplished by applying one's thumb and
adjacent finger(s) on opposite sides of the exterior wall 20 of the
tubular body 12 and squeezing the pliable tubular body 12. This
action imparts a positive pressure in the interior chamber 24 of
the tubular body 12 that is sufficient to cause the biological
fluid to flow through the filter assembly 18, causing particulate
material to be retained by the filter assembly 18 and resulting
clarified liquid to be expressed out of the device 10 through the
nozzle 80. The flow out of the device 10 is based on the biological
fluid composition, the filter pore size, and the amount of pressure
that can be generated by the fingers of the user when squeezing the
tubular body 12. It is believed by the inventors that only a few
psi are required to express the sample. Thus, the method of using
the device is fairly gentle in its processing requirements. The
length of the device 10 is based on allowing sufficient exposed
tubular body 12 for a user's fingers to grasp the device 10 between
the cap assembly 14 and the support assembly 16. If the tubular
body 12 is too long then insufficient pressure is generated to
express the full range of biological fluid types. The only
limitation on the length and shape of the tubular body 12 is the
ability to generate sufficient positive pressure in the interior
chamber 24 by hand squeezing the device 10.
As used herein, the term particulate material may be any solid
material which is separated from its liquid solution. Such
materials may include inorganic sorbant materials such as talc and
charcoal as well as glass beads. The solid material may also be
organic in nature such as sepharose, microcrystalline cellulose,
macroaggregated albumin and so forth. The materials may contain
ligands such antibodies, antigens or haptens. Other particulate
materials include, but not by way of limitation, bacteria, viruses,
yeast, cells, cell fragments, large chains of nucleic acids,
microorganisms, fragments of microorganisms, and large biological
complexes. Microorganism is meant to include the entire
microorganism or various forms or fragments the microorganism may
undergo during its life cycle.
If all of the biological fluid is not removed from the interior
chamber 24, the sealing cap 32 may be removed by pulling on the tab
42 with one's fingers with sufficient pressure to remove the cap
32. This allows air to enter the chamber 24. The device 10 is then
re-sealed and pressure re-applied. This step can be repeated until
all of the biological fluid is expressed from the chamber 24.
The method of use may end at this point if all that is desired is
filtration to produce a clarified liquid for further analysis of
the liquid such as through a diagnostic method for determination of
the presence or amount of one or more analytes in the liquid. The
device may simply be discarded in an appropriate biohazardous waste
container.
However, if extraction of analytes from the particulate matter is
desired for use in a further diagnostic assay method, the method of
use of the device 10 also includes an extraction procedure.
As used herein, analytes may be antigens, antibodies, receptors,
ligands, chelates, proteins, carbohydrates, enzymes,
polysaccharides, lipopolysacharrides, nucleic acids, DNA, RNA,
pesticides, herbicides, inorganic or organic compounds or any
material for which a specific binding reagent may be found.
Accordingly, the next step is to remove the sealing cap 32 from the
top 26 of the tubular body 12 by pulling on the 42 of the sealing
cap 32 with one's fingers. One or more extraction reagents are then
added to the interior chamber 24 of the tubular body 12. The type
of extraction reagent(s) used depends on the analyte(s) of
interest. Examples of extraction reagents that could be used, but
not by way of limitation, include protease extraction reagents,
alkaline detergent extraction reagents, lipase extraction reagents,
acidic extraction reagents, alkaline extraction reagents, reducing
extraction reagents, oxidizing extraction reagents, and organic
extraction reagents. One skilled in the art would know what
extraction reagent(s) to utilize to extract a desired analyte or
analytes from the particulate matter. The top 26 of the device 10
is then capped, and positive pressure is imparted to the inner
chamber 24 by squeezing on the exterior 20 of the pliable tubular
body 12. This causes the one or more reagents to contact the
particular matter retained in the filter assembly 18, breaking down
the particulate material, if present, so that an analyte or
analytes of interest are removed and the remaining particulate
material greater than the pore size of the filter assembly 18 is
left behind in the filter assembly 18. Simultaneously, the one or
more reagents and analyte(s), if present, are expressed from the
device 10 through the nozzle 80, into one or more extraction tubes
for further extraction or diagnostic assay. The filtration and
extraction device 10 is then discarded.
Examples of diagnostic assay methods include, but not by way of
limitation, radio-immunoassay (RIA), enzyme immunoassay (EIA),
fluorescent methods, chemiluminescence, surface plasmon resonance
(SPR), optical immunoassay (OIA), spectroscopic methods,
microscopic methods, and nucleic acid amplification methods. The
number of extraction tubes depends on the number of analytes that
are being tested for and the amount of extraction
reagents used.
The filtration and extraction device 10 of the present invention is
a simple, disposable, one-piece manual device that delivers a
clarified biological liquid and/or one or more different analytes
directly to an analytical method without the need for
centrifugation. Extraction of analytes from particulate material
retained in the device 10 can be accomplished in the same simple
device 10, without the need to re-suspend and transfer particulate
material from a centrifuge tube to an analysis tube. The device 10
also separates analytes from other larger particulates, eliminates
the need to re-centrifuge or filter an analyte and particulate
solution prior to analysis. Non-centrifugation manual filtering
devices such as syringe-type filtering devices have been developed,
but suffer from the drawbacks mentioned above in the background
section of the invention.
An exemplary use of the filtration and extraction device 10 of the
present invention will now be described with urine as the
biological fluid and a component or elementary body of Chlamydia
trachomatis (lipopolysacharride (LPS)) as the analyte to be
extracted from the retained particulate matter, i.e., Chlamydia
organisms. First, one milliliter of urine is removed from a
collection cup and transferred to the filtration and extraction
device 10. The device 10 is capped, and the urine is expressed from
the device 10 into an appropriate waste container by squeezing the
exterior 20 of the pliable tubular body 12. The device 10 is then
opened and two drops of a protease extraction reagent sold under
the trademark Chlamydia OIA Reagent 1A by BioStar, Inc. or Boulder,
Colo. is added to the chamber 24. The device 10 may rest in an
upright position on its flat bottom surface 58 on a bench top while
the reagents are added. The Reagent 1A is followed by the addition
of 6 drops of an alkaline detergent extraction reagent sold as
Chlamydia Reagent 1B by the BioStar, Inc. The device 10 is capped
and the combined extraction reagents are expressed from the device
10 into an extraction tube by squeezing the exterior 20 of the
pliable tubular body 12. Once all the reagent is expressed from the
device 10, the device 10 may be discarded into an appropriate
biohazardous waste container. Subsequently, 6 drops of neutralizer
sold as Reagent 2 by BioStar, Inc. may be added to the sample in
the extraction tube to neutralize the sample. By "neutralize" it is
meant the addition of a buffer system which achieves a final pH
range from 6.0 to 8.0. The sample in the extraction tube may then
be analyzed for detection of the Chlamydia trachomatis analyte
(LPS) using a test procedure such as the CHLAMYDIA OIA test
procedure by BioStar, Inc.
Another exemplary use of the filtration and extraction device 10 of
the present invention will now be described with urine as the
biological fluid and two analytes, components of Neisseria
gonorrhoeae (outer cell wall) and Chlamydia trachomatis (LPS), as
the analytes to be extracted from the retained particulate matter.
First, one milliliter of urine is removed from a collection cup and
transferred to the filtration and extraction device 10. The device
10 is capped, and the urine is expressed from the device 10 into an
appropriate waste container by squeezing the exterior 20 of the
pliable tubular body 12. The device 10 is then opened and 210
microliters of alkaline detergent extraction reagent sold as
Chlamydia OIA Reagent 1B by BioStar, Inc. is added to the chamber
24. The device 10 is capped and 50 microliters of extraction
reagent is expressed from the device 10 into an a first extraction
tube for determination of the Chlamydia trachomatis analyte (LPS)
and 100 microliters of extraction reagent is expressed into a
second extraction tube for determination of the Neisseria
gonorrhoeae analyte (outer cell wall). Once all of the reagent is
expressed from the device 10, the device 10 may be discarded into
an appropriate biohazards waste container.
In the first extraction tube, 14 microliters of protease extraction
reagent sold under the trademark Chlamydia OIA Reagent 1A is added
to the sample, and allowed to incubate for approximately two
minutes. Subsequently, 50 microliters of neutralization reagent
sold as Reagent 2 by BioStar, Inc. is added to the sample, and then
the resulting sample is analyzed in a Chlamydia assay, preferably
optical immunoassay, for detection of the Chlamydia trachomatis
analyte (LPS).
In the second extraction tube, 87 microliters of neutralization
reagent sold as Reagent 2 by BioStar, Inc. is added to the sample,
and then the resulting sample is analyzed in a Neisseria
gonorrhoeae assay, preferably an optical immunoassay, for detection
of the Neisseria gonorrhoeae analyte (outer cell wall).
The following is a table demonstrating data from the processing of
42 positive Chlamydia male urine samples. Samples were tissue
culture positive based on a urethral sample. One milliliter of
urine was filtered in the filtration and extraction device 10 of
the present invention and one milliliter of the same urine sample
was centrifuged to pellet the elementary bodies and cells in the
sample. The method of filtration and extraction was the same as
that described above for extraction of the Chlamydia trachomatis
analyte, and the assay method was the CHLAMYDIA OIA test procedure
by BioStar, Inc. The centrifuged sample was resuspended in
extraction media and then processed in the CHLAMYDIA OIA test
procedure. Tissue culture is considered the best means for
identification of the chlamydia infection. The filtration and
extraction device 10 (30/41=73.1%) performed very comparable to the
conventional centrifugation method (32/42=76.2%) in the recovery of
Chlamydia from a positive urine sample.
______________________________________ Specimen # Filtration and
Extraction Device Centrifugation Result
______________________________________ B1009 + - B1024 - - B1038 +
+ B1096 + + B1121 + + B1176 + - B1196 - - B1234 + + B0389 + + B0431
+ + B0495 + + B0508 + + B0525 - - B0529 - + B0721 + + B1017 + +
B1035 + + B1058 + + B0385 + + B0398 + + B0436 - - B0509 + + B0531 +
+ B0535 + + B0719 - + B0742 + + B0773 + + B1074 + + B1045 - + B1002
- - B0746 + + B1036 + + B0483 + + B0748 + + B0760 + + B1046 - -
B0594 + + B0570 + + B1034 + + B1016 - - B0754 + + B0710 - -
______________________________________
Although this invention has been described in terms of a preferred
embodiment, other embodiments apparent to those of ordinary skill
in the art are also within the scope of this invention.
Accordingly, the scope of the invention is intended to be defined
only by the claims that follow.
* * * * *